History

Originally called Atherdee, its name is derived from the Irish Áth Fhirdia (the Ford of Ferdia), from the mythological four day battle between Cúchulainn and Ferdia, for the defence of Ulster from Queen Maeve of Connacht. Ferdia fell after four days of battle and is buried on the southern banks of the river alongside the Riverside Walk. Ardee Castle in the town (St. Leger's) is the largest fortified medieval tower house in Ireland.

An eight km (five miles) railway line once linked the town to the main Dublin - Belfast line. The station opened on 1 August, 1896 and passenger services ended on 3 June, 1934. The line continued as a freight service until finally closed on 3 November, 1976, serving the local fertiliser factory, sugar beet, and livestock transport. The trackbed was lifted in the late 1980s, and much of the short route is now a designated walkway.

Also of note is "Jumping Church" which is located about five km (three miles) outside the town at Kildemock. Legend has it that a non-Christian was buried inside the Church walls and that later that night, the Church jumped so as to leave his remains outside of the sacred ground.